Light Neutralinos with Large Scattering Cross Sections in the Minimal Supersymmetric Standard Model

Motivated by recent data from CoGeNT and the DAMA annual modulation signal, we discuss collider constraints on MSSM neutralino dark matter with mass in the 5-15 GeV range. Such an LSP would be a Bino with a small Higgsino admixture. Maximization of the DM-nucleon scattering cross section for such a WIMP requires a light Higgs boson with tan beta enhanced couplings. Limits on the invisible width of the Z boson, when combined with Tevatron constraints on Higgs bosons at large tan beta, and the rare decay $B^{\pm} \to \tau \nu$ constrain cross sections to be below $\sigma_n \lesssim 2 \times 10^{-41} {cm}^2$. This indicates a slight local Dark Matter over-density would be necessary to explain the CoGeNT excess. This scenario also requires a light charged Higgs boson, which can give substantial contributions to rare decays such as $b \to s \gamma$ and $t \to b H^+$.Comment: 5 pages, 3 figures. v2: refs updated, minor typos corrected, new discussion on B->D\tau\nu, journal versio

An Online Assessment Strategy to Improve Student Engagement, Performance, and Retention: Certification-based Retesting

Many courses still utilize a traditional one chance testing model to assess student understanding. If the purpose of assessment is to reflect the mastery a student has in a course, then there is benefit for students to have multiple opportunities to show mastery. This paper outlines the results of a course policy of full grade replacement retesting that required students to first pass a “recertification” quiz. The goal of this policy was to adopt a pedagogical style that more readily reflected the opportunity of continued learning that many workers experience in the professional world while simultaneously aiming to engage students in an online course during the COVID-19 pandemic. A hypothesis test was conducted to determine if this retake policy helped to improve student grades during the course. The results indicate there was a statistically significant difference between the mean score on the first exam and the retest where, on average, students who utilized the exam retake increased their score. Time was found to have a positive relation with retest scores, but even after accounting for time, retesting was found to have a practical and significant effect on student performance. Retesting policies consistently show positive impacts on grades (e.g. Roszkowski & Spreat, 2016; Herman et al., 2019) and should be more widely considered when developing and updating course policies

The ASD Living Biology: from cell proliferation to clinical phenotype.

Autism spectrum disorder (ASD) has captured the attention of scientists, clinicians and the lay public because of its uncertain origins and striking and unexplained clinical heterogeneity. Here we review genetic, genomic, cellular, postmortem, animal model, and cell model evidence that shows ASD begins in the womb. This evidence leads to a new theory that ASD is a multistage, progressive disorder of brain development, spanning nearly all of prenatal life. ASD can begin as early as the 1st and 2nd trimester with disruption of cell proliferation and differentiation. It continues with disruption of neural migration, laminar disorganization, altered neuron maturation and neurite outgrowth, disruption of synaptogenesis and reduced neural network functioning. Among the most commonly reported high-confidence ASD (hcASD) genes, 94% express during prenatal life and affect these fetal processes in neocortex, amygdala, hippocampus, striatum and cerebellum. A majority of hcASD genes are pleiotropic, and affect proliferation/differentiation and/or synapse development. Proliferation and subsequent fetal stages can also be disrupted by maternal immune activation in the 1st trimester. Commonly implicated pathways, PI3K/AKT and RAS/ERK, are also pleiotropic and affect multiple fetal processes from proliferation through synapse and neural functional development. In different ASD individuals, variation in how and when these pleiotropic pathways are dysregulated, will lead to different, even opposing effects, producing prenatal as well as later neural and clinical heterogeneity. Thus, the pathogenesis of ASD is not set at one point in time and does not reside in one process, but rather is a cascade of prenatal pathogenic processes in the vast majority of ASD toddlers. Despite this new knowledge and theory that ASD biology begins in the womb, current research methods have not provided individualized information: What are the fetal processes and early-age molecular and cellular differences that underlie ASD in each individual child? Without such individualized knowledge, rapid advances in biological-based diagnostic, prognostic, and precision medicine treatments cannot occur. Missing, therefore, is what we call ASD Living Biology. This is a conceptual and paradigm shift towards a focus on the abnormal prenatal processes underlying ASD within each living individual. The concept emphasizes the specific need for foundational knowledge of a living child's development from abnormal prenatal beginnings to early clinical stages. The ASD Living Biology paradigm seeks this knowledge by linking genetic and in vitro prenatal molecular, cellular and neural measurements with in vivo post-natal molecular, neural and clinical presentation and progression in each ASD child. We review the first such study, which confirms the multistage fetal nature of ASD and provides the first in vitro fetal-stage explanation for in vivo early brain overgrowth. Within-child ASD Living Biology is a novel research concept we coin here that advocates the integration of in vitro prenatal and in vivo early post-natal information to generate individualized and group-level explanations, clinically useful prognoses, and precision medicine approaches that are truly beneficial for the individual infant and toddler with ASD

Retroviral Expression of Transforming Growth Factor-Alpha Does Not Transform Fibroblasts or Keratinocytes

Transforming growth factor α (TGFα) is a peptide so named because it helps to impart anchorage-independent growth to normal rat kidney (NRK) cells in vitro and is secreted by many rodent and human tumor cells. To directly investigate the transforming properties of this factor, we constructed a replication-defective murine retrovirus that expresses the human sequence coding for TGFα. infection of NIH/3T3 cells with the TGFα retrovirus led to the integration of a transcriptionally active provirus and overexpression of biologically active TGFα, but failed to induce morphologic transformation. Similarly, the TGFα retrovirus failed to induce morphologic transformation of five other types of rodent fibroblasts.We also investigated the effect of TGFα expression on the growth of BALB/MK mouse keratinocytes, which require epidermal growth factor (EGF) for proliferation. We show that exogenously added TGFα is an extremely potent mitogen for BALB/MK cells. However, retroviral expression of TGFa in BALB/MK cells failed to relieve dependence on exogenously added EGF (or TGFα) for cell growth. These results suggest that overexpression of TGFα does not, by itself, transform rodent fibroblasts or keratinocytes

Packet-Level Diversity - From Theory to Practice: An 802.11-based Experimental Investigation

Packet-level diversity, or the ability to distribute packet transmissions over multiple, diverse channels, offers a number of benefits in improving communication performance and robustness to variations in channel quality. There have been a number of works that have analyzed and quantified those benefits, and developed transmission policies to realize them. However, translating those potential benefits into practice still faces numerous challenges. These range from uncertainty regarding the adequacy of the channel models on which the development of policies was predicated, to the many implementation constraints one faces when attempting to realize the precise transmission schedules that these policies mandate. This work is an initial step in assessing how much of the benefit that packet-level diversity promises actually remains once confronted with the many practical challenges we have just alluded to. Our investigation is carried out in the context of an 802.11 testbed, where diversity is realized through the different frequency bands available for transmissions between hosts and access points. We use our testbed to evaluate the impact of various parameters, including transmission policies, channel characteristics, channel correlation, and various end-system constraints that affect our ability to precisely control the timing of transmissions. Our investigation reveals that in spite of the many gaps that exist between theory and practice, packet-level diversity still provides a simple solution to improving transmission performance and robustness across a broad range of configurations

Systematically Searching for New Resonances at the Energy Frontier using Topological Models

We propose a new strategy to systematically search for new physics processes in particle collisions at the energy frontier. An examination of all possible topologies which give identifiable resonant features in a specific final state leads to a tractable number of `topological models' per final state and gives specific guidance for their discovery. Using one specific final state, $\ell\ell jj$, as an example, we find that the number of possibilities is reasonable and reveals simple, but as-yet-unexplored, topologies which contain significant discovery potential. We propose analysis techniques and estimate the sensitivity for $pp$ collisions with $\sqrt{s}=14$ TeV and $\mathcal{L}=300$ fb$^{-1}$

Designing everyday technologies with human-power and interactive microgeneration

ABSTRACT This paper creatively explores and critically inquires into power and energy at scales at which it can be generated by human bodily kinetic motion, with goals of promoting more engaging, meaningful, and sustainable interactions with and through interactive technology and electricity. To do so we delineate and name the research and design space of interactive microgeneration (IμG) and the subarea of humanpower microgeneration (HPμG). We then present findings from a qualitative study employing (i) novel design prototypes we designed (e.g., a hand-powered mobile phone), (ii) commercially available products (e.g., a solar phone charger), and (iii) common everyday products (e.g., a kitchen knife, a food processor). Our empirical study and design explorations point to new design and research opportunities and challenges related to the generation and consumption of electrical energy in everyday life